He says Mr Alvarenga may have benefitted from environmental factors in this part of the world, particularly the prevalence of fresh rain water and animal life.

“He and other people who have been in the Pacific seem to have a better chance of surviving long-term,” Mr Vroomans said.

“The environmental conditions on the Pacific side (of Mexico), particularly around South America and Central America, are quite conducive to people being able to find food and get water.

“Obviously you would be able to pick up rain water because it would appear he had no method of making salt water safe to drink.”

Mr Vroomans says drinking your own urine – which Mr Alvarenga says he did – is only beneficial if you are otherwise hydrated.

But catching fish and birds would have been possible given that, out on the ocean, both would have congregated near the boat as a place to shelter and feed.

“Small fish come underneath boats because it’s shady and it’s cooler; where you have small fish, you have large fish,” Mr Vroomans said.

Mr Vroomans says it is possible to eat both species raw – provided you stay away from the fish guts – and that the sailor’s claim he drank turtle blood makes sense.

“I’ve had turtle blood myself and it is extremely rich in protein,” Mr Vroomans said.

“That would have made a massive difference to him. Protein is very important in a survival situation because you need to repair your body tissues.”

Survival expert Bob Cooper says the story is believable because of the type of vessel Mr Alvarenga was on.

“That would have had a bunk and it probably would have had good shade,” he said.

Surface currents add heft to ‘remarkable’ drift story

Oceanographers say it is possible, given the prevailing winds and currents, for a boat drifting from western Mexico to end up in the Marshall Islands.

University of Technology Sydney senior research fellow Martina Doblin says the general direction of surface currents in the Pacific Ocean is consistent with the westward movement of Mr Alvarenga’s vessel.

“It is still absolutely remarkable, though,” she said.

A 1953 study by an American oceanographer that tracked the pumice spewed from the eruption of a volcano on Mexico’s west coast found it did reach the Marshall Islands.

It moved 18 centimetres per second, taking about 560 days to reach the remote group of islands.

Psychological aspect of situation a major issue

Mr Cooper says how Mr Alvarenga dealt with his situation psychologically would have been a major factor in his survival.

“Some people have been in less stressful situations and just given up,” he said.

“Survival is a mind game – never, ever give up.”

Mr Vroomans agrees, adding that the possibility of rescue would have presented a significant psychological challenge.

“It would be interesting to find out how many boats went past him that didn’t see him, and how many times he thought he might be rescued but wasn’t.”

He says, in survival situations, accepting your circumstances can lead you to make more logical decisions.

“Some people fall into despair and they end up dying very quickly,” he said.

Mr Alvarenga is being treated for dehydration and joint pain in the Marshall Islands capital Majuro but is in a stable condition.

Mr Bing said Mr Alvarenga had been fingerprinted to confirm his identity and the government was trying to communicate with Mexican and El Salvador authorities regarding repatriation.